Mycobacterium tuberculosis infection induces IL-10 gene expression by disturbing histone deacetylase 6 and histonedeacetylase 11 equilibrium in macrophages

Immune-endocrine network in diabetes-tuberculosis nexus: does latent tuberculosis infection confer protection against meta-inflammation and insulin resistance?

Tuberculosis patients with diabetes, have higher sputum bacillary load, delayed sputum conversion, higher rates of drug resistance, higher lung cavitary involvement and extra-pulmonary TB infection, which is called as "Diabetes-Tuberculosis Nexus". However, recently we have shown a reciprocal relationship between latent tuberculosis infection and insulin resistance, which has not been reported before. In this review, we would first discuss about the immune-endocrine network, which operates during pre-diabetes and incipient diabetes and how it confers protection against LTBI. The ability of IR to augment anti-TB immunity and the immunomodulatory effect of LTBI to quench IR were discussed, under IR-LTB antagonism. The ability of diabetes to impair anti-TB immunity and ability of active TB to worsen glycemic control, were discussed under "Diabetes-Tuberculosis Synergy". The concept of "Fighter Genes" and how they confer protection against TB but susceptibility to IR was elaborated. Finally, we conclude with an evolutionary perspective about how IR and LTBI co-evolved in endemic zones, and have explained the molecular basis of "IR-LTB" Antagonism" and "DM-TB Synergy", from an evolutionary perspective.

Epigenetic orchestration of host immune defences by Mycobacterium tuberculosis

Being among the top 10 causes of adult deaths, tuberculosis (TB) disease is considered a major global public health concern to address. The human tuberculosis pathogen, Mycobacterium tuberculosis (Mtb), is an extremely competent and well-versed pathogen that promotes pathogenesis by evading the host immune systems through numerous tactics. Investigations revealed that Mtb could evade the host defense mechanisms by reconfiguring the host gene transcription and causing epigenetic changes. Although results indicate the link between epigenetics and disease manifestation in other bacterial infections, little is known regarding the kinetics of the epigenetic alterations in mycobacterial infection. This literature review discusses the studies in Mtb-induced epigenetic alterations inside the host and its contribution in the host immune evasion strategies. It also discusses how the Mtb-induced alterations could be used as 'epibiomarkers' to diagnose TB. Additionally, this review also discusses therapeutic interventions to be enhanced through remodification by 'epidrugs'.

Non-covalent π-π functionalized Gii-senseⓇ graphene foam for interleukin 10 impedimetric detection

Monitoring Interleukin 10 (IL-10) is essential for understanding the vast responses of T-cells in cancer, autoimmunity, and internal homeostasis after physical stress. However, current diagnostic methods are complex and more focused on medical screening rather than point-of-care monitoring. Biosensors based on graphene's conductivity and flexibility are attractive to offer simple single-use and reduced handling. However, oxidation of its carbon lattice to develop functional moieties for biomolecule immobilization cuts down its electronic conductivity potential. In this work, the authors present a microfluidic lab-on-chip device for simple impedimetric monitoring of IL-10 based on graphene foam (GF) flexible electrodes. Graphene's structure was maintained by employing π-π non-covalent functionalization with pyrene carboxylic acid (PCA). Impedimetric measurements could be performed in low ionic strength phosphate-buffered saline (LI-PBS). The PCA-antibody modification showed to endure the incubation, measurement, and washing processes performed in the microfluidic device. Electrode modification and measurements were characterized by, electrochemical impedance spectroscopy (EIS), contact angle, and scanning electron microscopy. From the contact angle results, we found that the wettability of the graphene surface increased gradually after each modification step. Detection measurements performed in the 3D-printed microfluidic device showed a linear response between 10 fg/mL to 100 fg/mL with a limit of detection (LOD) of 7.89 fg/mL in artificial saliva. With these features, the device was used to quantify IL-10 samples by the standard addition method for 10 fg and 50 fg with recoveries between 82% and 99%. Specificity was evaluated towards interleukin 6, TNF-⍺ and bovine serum albumin.

Bacteria and macrophages in the tumor microenvironment

Cancer and microbial infections are significant worldwide health challenges. Numerous studies have demonstrated that bacteria may contribute to the emergence of cancer. In this review, we assemble bacterial species discovered in various cancers to describe their variety and specificity. The relationship between bacteria and macrophages in cancer is also highlighted, and we look for ample proof to establish a biological basis for bacterial-induced macrophage polarization. Finally, we quickly go over the potential roles of metabolites, cytokines, and microRNAs in the regulation of the tumor microenvironment by bacterially activated macrophages. The complexity of bacteria and macrophages in cancer will be revealed as we gain a better understanding of their pathogenic mechanisms, which will lead to new therapeutic approaches for both inflammatory illnesses and cancer.

LncRNA HDAC11-AS1 Suppresses Atherosclerosis by Inhibiting HDAC11-Mediated Adropin Histone Deacetylation

LncRNA HDAC11-AS1 (HDAC11-AS1) is the natural antisense transcript of HDAC11, a key enzyme for DNA histone deacetylation. We evaluated the role of HDAC11-AS1 in atherosclerosis. In this research, we found that HDAC11-AS1 ameliorated blood lipid levels and atherosclerosis in high fat-dieted apoE-/- mice by regulating HDAC11 negatively. The change in blood lipid levels is related to the expression of LPL, which is enhanced by HDAC11-AS1 through regulating adropin histone deacetylation in vitro and in vivo. In conclusion, HDAC11-AS1 plays an anti-atherogenic role through adropin to induce LPL expressions, thereby enhancing TG metabolism. The results are valuable for the further development of HDAC11-AS1 and its clinical applications. It provides a new clinical therapeutic target for cardiovascular disease treatment.

HDAC11, an emerging therapeutic target for metabolic disorders

Histone deacetylase 11 (HDAC11) is the only member of the class IV HDAC, and the latest member identified. It is highly expressed in brain, heart, kidney and some other organs, and located in mitochondria, cytoplasm and nuclei, depending on the tissue and cell types. Although studies in HDAC11 total knockout mice suggest its dispensable features for tissue development and life, it participates in diverse pathophysiological processes, such as DNA replication, tumor growth, immune regulation, oxidant stress injury and neurological function of cocaine. Recent studies have shown that HDAC11 is also critically involved in the pathogenesis of some metabolic diseases, including obesity, diabetes and complications of diabetes. In this review, we summarize the recent progress on the role and mechanism of HDAC11 in the regulation of metabolic disorders, with the focus on its regulation on adipogenesis, lipid metabolism, metabolic inflammation, glucose tolerance, immune responses and energy consumption. We also discuss the property and selectivity of HDAC11 inhibitors and their applications in a variety of in vitro and in vivo models of metabolic disorders. Given that pharmacological and genetic inhibition of HDAC11 exerts a beneficial effect on various metabolic disorders, HDAC11 may be a potential therapeutic target to treat chronic metabolic diseases.

Critical Functions of Histone Deacetylases (HDACs) in Modulating Inflammation Associated with Cardiovascular Diseases

Histone deacetylases (HDACs) are a superfamily of enzymes that catalyze the removal of acetyl functional groups from lysine residues of histone and non-histone proteins. There are 18 mammalian HDACs, which are classified into four classes based on the primary homology with yeast HDACs. Among these groups, Class I and II HDACs play a major role in lysine deacetylation of the N-terminal histone tails. In mammals, HDACs play a pivotal role in the regulation of gene transcription, cell growth, survival, and proliferation. HDACs regulate the expression of inflammatory genes, as evidenced by the potent anti-inflammatory activity of pan-HDAC inhibitors, which were implicated in several pathophysiologic states in the inflammation process. However, it is unclear how each of the 18 HDAC proteins specifically contributes to the inflammatory gene expression. It is firmly established that inflammation and its inability to converge are central mechanisms in the pathogenesis of several cardiovascular diseases (CVDs). Emerging evidence supports the hypothesis that several different pro-inflammatory cytokines regulated by HDACs are associated with various CVDs. Based on this hypothesis, the potential for the treatment of CVDs with HDAC inhibitors has recently begun to attract attention. In this review, we will briefly discuss (1) pathophysiology of inflammation in cardiovascular disease, (2) the function of HDACs in the regulation of atherosclerosis and cardiovascular diseases, and (3) the possible therapeutic implications of HDAC inhibitors in cardiovascular diseases. Recent studies reveal that histone deacetylase contributes critically to mediating the pathophysiology of inflammation in cardiovascular disease. HDACs are also recognized as one of the major mechanisms in the regulation of inflammation and cardiovascular function. HDACs show promise in developing potential therapeutic implications of HDAC inhibitors in cardiovascular and inflammatory diseases.

Profiling the immune response to Mycobacterium tuberculosis Beijing family infection: a perspective from the transcriptome

Tuberculosis continues to be an important public health problem. Particularly considering Beijing-family strains of Mycobacterium tuberculosis, which have been associated with drug-resistance and hypervirulence. The Beijing-like SIT190 (BL) is the most prevalent Beijing strain in Colombia. The pathogenic mechanism and immune response against this pathogen is unknown. Thus, we compared the course of pulmonary TB in BALB/c mice infected with Classical-Beijing strain 391 and BL strain 323. The disease course was different among infected animals with Classical-Beijing and BL strain. Mice infected with BL had a 100% mortality at 45 days post-infection (dpi), with high bacillary loads and massive pneumonia, whereas infected animals with Classical-Beijing survived until 60 dpi and showed extensive pneumonia and necrosis. Lung RNA extraction was carried out at early (day 3 dpi), intermediate (day 14 dpi), and late (days 28 and 60 dpi) time points of infection. Transcriptional analysis of infected mice with Classical-Beijing showed several over-expressed genes, associated with a pro-inflammatory profile, including those for coding for CCL3 and CCL4 chemokines, both biomarkers of disease severity. Conversely, mice infected with BL displayed a profile which included the over-expression of several genes associated with immune-suppression, including Nkiras, Dleu2, and Sphk2, highlighting an anti-inflammatory milieu which would allow high bacterial replication followed by an intense inflammatory response. In summary, both Beijing strains induced a non-protective immune response which induced extensive tissue damage, BL strain induced rapidly extensive pneumonia and death, whereas Classical-Beijing strain produced slower extensive pneumonia later associated with extensive necrosis.

RNA-Seq Transcriptome Analysis of Peripheral Blood From Cattle Infected With Mycobacterium bovis Across an Experimental Time Course

Bovine tuberculosis, caused by infection with members of the Mycobacterium tuberculosis complex, particularly Mycobacterium bovis, is a major endemic disease affecting cattle populations worldwide, despite the implementation of stringent surveillance and control programs in many countries. The development of high-throughput functional genomics technologies, including RNA sequencing, has enabled detailed analysis of the host transcriptome to M. bovis infection, particularly at the macrophage and peripheral blood level. In the present study, we have analysed the transcriptome of bovine whole peripheral blood samples collected at −1 week pre-infection and +1, +2, +6, +10, and +12 weeks post-infection time points. Differentially expressed genes were catalogued and evaluated at each post-infection time point relative to the −1 week pre-infection time point and used for the identification of putative candidate host transcriptional biomarkers for M. bovis infection. Differentially expressed gene sets were also used for examination of cellular pathways associated with the host response to M. bovis infection, construction of de novo gene interaction networks enriched for host differentially expressed genes, and time-series analyses to identify functionally important groups of genes displaying similar patterns of expression across the infection time course. A notable outcome of these analyses was identification of a 19-gene transcriptional biosignature of infection consisting of genes increased in expression across the time course from +1 week to +12 weeks post-infection.

Metabolic Regulation of Immune Responses to Mycobacterium tuberculosis: A Spotlight on L-Arginine and L-Tryptophan Metabolism

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is a leading cause of death worldwide. Despite decades of research, there is still much to be uncovered regarding the immune response to Mtb infection. Here, we summarize the current knowledge on anti-Mtb immunity, with a spotlight on immune cell amino acid metabolism. Specifically, we discuss L-arginine and L-tryptophan, focusing on their requirements, regulatory roles, and potential use as adjunctive therapy in TB patients. By continuing to uncover the immune cell contribution during Mtb infection and how amino acid utilization regulates their functions, it is anticipated that novel host-directed therapies may be developed and/or refined, helping to eradicate TB.

The role of HDAC11 in obesity-related metabolic disorders: A critical review

At present, metabolic diseases, such as obesity and diabetes, have become the world's top health threats. These diseases are closely related to the abnormal development and function of adipocytes and metabolic inflammation associated with obesity. Histone deacetylase 11 (HDAC11), with a relatively unique structure and function in the HDAC family, plays a vital role in regulating cell growth, migration, and cell death. Currently, research on new key regulatory functions of HDAC11 in metabolic homeostasis is receiving more and more attention, and HDAC11 has also become a potential therapeutic target in the treatment of obesity and obesity-related diseases. Here, we summarized the latest literature on the role of HDAC11 in regulating the progress of obesity-related metabolic disorders.

Role of Epigenetics in the Regulation of Immune Functions of the Skin

This review is intended to illuminate the emerging understanding of epigenetic modifications that regulate both adaptive and innate immunity in the skin. Host defense of the epidermis and dermis involves the interplay of many cell types to enable homeostasis; tolerance to the external environment; and appropriate response to transient microbial, chemical, and physical insults. To understand this process, the study of cutaneous immunology has focused on immune responses that reflect both adaptive learned and genetically programmed innate defense systems. However, recent advances have begun to reveal that epigenetic modifications of chromatin structure also have a major influence on the skin immune system. This deeper understanding of how enzymatic changes in chromatin structure can modify the skin immune system and may explain how environmental exposures during life, and the microbiome, lead to both short-term and long-term changes in cutaneous allergic and other inflammatory processes. Understanding the mechanisms responsible for alterations in gene and chromatin structure within skin immunocytes could provide key insights into the pathogenesis of inflammatory skin diseases that have thus far evaded understanding by dermatologists.

HDAC11: a rising star in epigenetics

Epigenetic mechanisms, such as acetylation, methylation, and succinylation, play pivotal roles in the regulation of multiple normal biological processes, including neuron regulation, hematopoiesis, bone cell maturation, and metabolism. In addition, epigenetic mechanisms are closely associated with the pathological processes of various diseases, such as metabolic diseases, autoimmune diseases and cancers. Epigenetic changes may precede genetic mutation, so research on epigenetic changes and regulation may be important for the early detection and diagnosis of disease. Histone deacetylase11 (HDAC11) is the newest member of the histone deacetylase (HDAC) family and the only class IV histone deacetylase. HDAC11 has different expression levels and biological functions in different systems of the human body and is among the top 1 to 4% of genes overexpressed in cancers, such as breast cancer, hepatocellular carcinoma and renal pelvis urothelial carcinoma. This article analyzes the role and mechanism of HDAC11 in disease, especially in tumorigenesis, in an attempt to provide new ideas for clinical and basic research.

The inter-talk between Mycobacterium tuberculosis and the epigenetic mechanisms

Epigenetics regulate gene function without any alteration in the DNA sequence. The epigenetics represent one of the most important regulators in different cellular processes and have initially been developed in microorganisms as a protective strategy. The evaluation of the epigenetic mechanisms is also important in achieving an efficient control strategy in tuberculosis (TB). TB is one of the most significant epidemiological concerns in human history. Despite several in vivo and in vitro studies that have evaluated different epigenetic modifications in TB, many aspects of the association between epigenetics and TB are not fully understood. The current paper is aimed at reviewing our knowledge on histone modifications and DNA methylation modifications, as well as miRNAs regulation in TB.

Functional Inhibition of Host Histone Deacetylases (HDACs) Enhances in vitro and in vivo Anti-mycobacterial Activity in Human Macrophages and in Zebrafish

The rapid and persistent increase of drug-resistant Mycobacterium tuberculosis (Mtb) infections poses increasing global problems in combatting tuberculosis (TB), prompting for the development of alternative strategies including host-directed therapy (HDT). Since Mtb is an intracellular pathogen with a remarkable ability to manipulate host intracellular signaling pathways to escape from host defense, pharmacological reprogramming of the immune system represents a novel, potentially powerful therapeutic strategy that should be effective also against drug-resistant Mtb. Here, we found that host-pathogen interactions in Mtb-infected primary human macrophages affected host epigenetic features by modifying histone deacetylase (HDAC) transcriptomic levels. In addition, broad spectrum inhibition of HDACs enhanced the antimicrobial response of both pro-inflammatory macrophages (Mϕ1) and anti-inflammatory macrophages (Mϕ2), while selective inhibition of class IIa HDACs mainly decreased bacterial outgrowth in Mϕ2. Moreover, chemical inhibition of HDAC activity during differentiation polarized macrophages into a more bactericidal phenotype with a concomitant decrease in the secretion levels of inflammatory cytokines. Importantly, in vivo chemical inhibition of HDAC activity in Mycobacterium marinum-infected zebrafish embryos, a well-characterized animal model for tuberculosis, significantly reduced mycobacterial burden, validating our in vitro findings in primary human macrophages. Collectively, these data identify HDACs as druggable host targets for HDT against intracellular Mtb.

Epigenetic Modification in Macrophages: A Promising Target for Tumor and Inflammation-associated Disease Therapy

Macrophages are essential for supporting tissue homeostasis, regulating immune response, and promoting tumor progression. Due to its heterogeneity, macrophages have different phenotypes and functions in various tissues and diseases. It is becoming clear that epigenetic modification playing an essential role in determining the biological behavior of cells. In particular, changes of DNA methylation, histone methylation and acetylation regulated by the corresponding epigenetic enzymes, can directly control macrophages differentiation and change their functions under different conditions. In addition, epigenetic enzymes also have become anti-tumor targets, such as HDAC, LSD1, DNMT, and so on. In this review, we presented an overview of the latest progress in the study of macrophages phenotype and function regulated by epigenetic modifications, including DNA methylation and histone modifications, to better understand how epigenetic modification controls macrophages phenotype and function in inflammation-associated diseases, and the application prospect in anti-tumor.

Interleukin 10 knock-down in bovine monocyte-derived macrophages has distinct effects during infection with two divergent strains of Mycobacterium bovis

Mycobacterium bovis is the causative agent of bovine tuberculosis (TB), a cattle disease of global importance. M. bovis infects bovine macrophages (Mø) and subverts the host cell response to generate a suitable niche for survival and replication. We investigated the role of the anti-inflammatory cytokine interleukin (IL) 10 during in vitro infection of bovine monocyte-derived Mø (bMDM) with two divergent UK strains of M. bovis, which differentially modulate expression of IL10. The use of IL10-targeting siRNA revealed that IL10 inhibited the production of IL1B, IL6, tumour necrosis factor (TNF) and interferon gamma (IFNG) during infection of bMDM with the M. bovis strain G18. In contrast, IL10 only regulated a subset of these genes; TNF and IFNG, during infection with the M. bovis reference strain AF2122/97. Furthermore, nitric oxide (NO) production was modulated by IL10 during AF2122/97 infection, but not at the nitric oxide synthase 2 (NOS2) mRNA level, as observed during G18 infection. However, IL10 was found to promote survival of both M. bovis strains during early bMDM infection, but this effect disappeared after 24 h. The role of IL10-induced modulation of TNF, IFNG and NO production in M. bovis survival was investigated using siRNA targeting TNF, IFNG receptor 1 (IFNGR1) and NOS2. Knock-down of these genes individually did not promote survival of either M. bovis strain and therefore modulation of these genes does not account for the effect of IL10 on M. bovis survival. However, TNF knock-down was found to be detrimental to the survival of the M. bovis strain G18 during early infection. The results provide further evidence for the importance of IL10 during M. bovis infection of Mø. Furthermore, they highlight M. bovis strain specific differences in the interaction with the infected bMDM, which may influence the course of infection and progression of bovine TB.

Selective HDAC6 inhibitors improve anti-PD-1 immune checkpoint blockade therapy by decreasing the anti-inflammatory phenotype of macrophages and down-regulation of immunosuppressive proteins in tumor cells

Histone deacetylases (HDACs) are involved in diverse cellular regulatory mechanisms including non-canonical functions outside the chromatin environment. Several publications have demonstrated that selective HDAC inhibitors (HDACi) can influence tumor immunogenicity and the functional activity of specific immune cells. In particular, the selective inhibition of HDAC6 has been reported to decrease tumor growth in several malignancies. However, there is still no clarity about the cellular components mediating this effect. In this study, we evaluated the HDAC6i Nexturastat A as a priming agent to facilitate the transition of the tumor microenvironment from “cold” to “hot”, and potentially augment immune check-point blockade therapies. This combination modality demonstrated to significantly reduce tumor growth in syngeneic melanoma tumor models. Additionally, we observed a complete neutralization of the up-regulation of PD-L1 and other immunosuppressive pathways induced by the treatment with anti-PD-1 blockade. This combination also showed profound changes in the tumor microenvironment such as enhanced infiltration of immune cells, increased central and effector T cell memory, and a significant reduction of pro-tumorigenic M2 macrophages. The evaluation of individual components of the tumor microenvironment suggested that the in vivo anti-tumor activity of HDAC6i is mediated by its effect on tumor cells and tumor-associated macrophages, and not directly over T cells. Overall, our results indicate that selective HDAC6i could be used as immunological priming agents to sensitize immunologically “cold” tumors and subsequently improve ongoing immune check-point blockade therapies.

Regulation of Chemokines and Cytokines by Histone Deacetylases and an Update on Histone Decetylase Inhibitors in Human Diseases

Histone acetyltransferases (HATs) and histone deacetylases (HDACs) counteract with each other to regulate gene expression by altering chromatin structure. Aberrant HDAC activity was reported in many human diseases including wide range of cancers, viral infections, cardiovascular complications, auto-immune diseases and kidney diseases. HDAC inhibitors are small molecules designed to block the malignant activity of HDACs. Chemokines and cytokines control inflammation, immunological and other key biological processes and are shown to be involved in various malignancies. Various HDACs and HDAC inhibitors were reported to regulate chemokines and cytokines. Even though HDAC inhibitors have remarkable anti-tumor activity in hematological cancers, they are not effective in treating many diseases and many patients relapse after treatment. However, the role of HDACs and cytokines in regulating these diseases still remain unclear. Therefore, understanding exact mechanisms and effector functions of HDACs are urgently needed to selectively inhibit them and to establish better a platform to combat various malignancies. In this review, we address regulation of chemokines and cytokines by HDACs and HDAC inhibitors and update on HDAC inhibitors in human diseases.

Evaluation of the expression of cytokines and chemokines in macrophages in response to rifampin-monoresistant Mycobacterium tuberculosis and H37Rv strain

Macrophages are the primary phagocytes in the lungs and a part of the host defense system against Mycobacterium tuberculosis (Mtb), involved in the primary immune response. While several studies have assessed the effects of resistance to rifampin on Mtb physiology, the consequences of mutations in genes encoding the beta subunit of RNA polymerase (rpoB) for host-pathogen interactions remain poorly understood. In this study, rifampin-monoresistant (RMR) Mtb and H37Rv strains were used to infect the THP-1-derived macrophages. Real-time quantitative reverse transcription PCR assay was carried out to determine mRNA expression in 84 cytokine and chemokine genes. Production of specific cytokines and chemokines was measured by ELISA assay. In conclusion, the current study shed more light on the fitness cost of RMR strain and the potential effects of rpoB gene mutations on Mtb-host interactions. These results initially demonstrate that the Mtb carrying the rpoB-S450L can modulate macrophage responses to mediate bacterial survival.

Potential Effect of Statins on Mycobacterium tuberculosis Infection

Tuberculosis is one of the 10 leading causes of death in the world. The current treatment is based on a combination of antimicrobials administered for six months. It is essential to find therapeutic agents with which the treatment time can be shortened and strengthen the host immune response against Mycobacterium tuberculosis. M. tuberculosis needs cholesterol to infect and survive inside the host, but the progression of the infection depends to a large extent on the capacity of the immune response to contain the infection. Statins inhibit the synthesis of cholesterol and have pleiotropic effects on the immune system, which have been associated with better results in the treatment of several infectious diseases. Recently, it has been reported that cells treated with statins are more resistant to M. tuberculosis infection, and they have even been proposed as adjuvants in the treatment of M. tuberculosis infection. The aim of this review is to summarize the immunopathogenesis of tuberculosis and its mechanisms of evasion and to compile the available scientific information on the effect of statins in the treatment of tuberculosis.